Ventilator breath display and graphic user interface

ABSTRACT

The invention is directed to a ventilation control system for controlling the ventilation of a patient. The ventilation control system utilizes a user-friendly user interface for the display of patient data and ventilator status. The user interface includes a graphic representation of a breath cycle that displays the breath cycle currently being ventilated, and is also responsive to changes in ventilation settings to assist the user in evaluation the effect of those changes on the ventilator strategy before the changes are implemented.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates generally to the field of medicalequipment for respiratory therapy and more specifically to the userinterface for a ventilator used for monitoring and controlling thebreathing of a patient.

[0003] 2. Description Of The Related Art

[0004] Modern patient ventilators are designed to ventilate a patient'slungs with breathing gas, and to thereby assist a patient when thepatient's ability to breathe on his own is somehow impaired. As researchhas continued in the field of respiration therapy, a wide range ofventilation strategies have been developed. For example, pressureassisted ventilation is a strategy often available in patientventilators and includes the supply of pressure assistance when thepatient has already begun an inspiratory effort. With such a strategy,it is desirable to immediately increase the pressure after a breath isinitiated in order to reach a target airway pressure for the pressureassistance. This rise in pressure in the patient airway which suppliesbreathing gas to the patient's lungs allows the lungs to be filled withless work of breathing by the patent. Conventional pressure assistedventilator systems typically implement a gas flow control strategy ofstabilizing pressure support after a target pressure is reached to limitpatient airway pressure. Such a strategy also can include programmedreductions in the patient airway pressure after set periods of therespiratory cycle in order to prepare for initiation of the next patientbreath.

[0005] As patient ventilator systems and their various components,including sensors and control systems, have become more sophisticated,and more understanding is gained about the physiology of breathing andthe infirmities and damage which form the requirements for respiratorytherapy, the number of variables to be controlled and the timing andinterrelationships between the parameters have begun to confront thecaregiver with a daunting number of alternative therapeutic alternativesand ventilator settings. Also, in such a complex environment, theinterface between the ventilator and the caregiver has often not beenadaptable to the capabilities of the operator, thus running the chanceof either limiting the choices available to a sophisticated user orallowing a relatively less sophisticated user to chose poorly from thealternatives presented. Thus, it would be beneficial if a ventilatorinterface guided the user through the setup or therapy modificationprocess, illustrating the relationship between changes, preventingincorrect or dangerous settings and sounding alarms or other audibleindications of invalid settings when something is about to done thatexceeds limits, but also allowing the advanced and sophisticated user togain access to the full range of ventilator capabilities through aninterface which both presents the various parameters and allows thevisualization of their relationships.

[0006] Clinical treatment of a ventilated patient often requires thatthe breathing characteristics of the patient be monitored to detectchanges in the breathing patterns of the patient. Many modernventilators allow the visualization of patient breathing patterns andventilator function and the caregiver adjusts the settings of theventilator to fine tune the respiratory strategy being performed toassist the patient's breathing. However, these systems have been, upuntil now, relatively difficult to use by the unsophisticated userunless a limited number of options are selected. For example, in oneprior art system, only a single respiratory parameter may be altered ata time. Moreover, the various respiratory parameters must often beentered into the ventilator controller in a prescribed order, or, whereno order is prescribed, certain orders of entry should be avoided,otherwise the intermediate state of the machine before entry of theremaining parameters may not be appropriate for the patient. Thisinflexible approach to ventilator setup requires additional time andtraining if the user is to quickly and efficiently use the ventilator ina critical care environment.

[0007] Previous systems have also been deficient in that it is oftendifficult to determine the underlying fault that has caused an alarms tobe sounded, and what controls or settings should be adjusted to cure theproblem causing the alarm. For example, prior alarm systems haveconsisted of nothing more than a blinking display or light with an alarmto alert the user that a problem existed. Similarly, many prior artsystems provided only limited assistance to a user or technician insetting the parameters to be used during treatment. For example, if atechnician attempted to enter a setting that was inappropriate for thepatient because of body size or for some other reason, the only alarmprovided may have been an auditory indication that the value was notpermitted, but no useful information was provided to assist thetechnician in entering an appropriate setting.

[0008] One problem consistently presented by prior art ventilatorcontrol systems has been that the user interface has offered relativelylittle to guide and inform the user during the setup and use of theventilator. Prior systems typically utilized a single visual display ofthe operating parameters of the ventilator and sensed patientparameters. Alternatively, prior systems may have numerous fixed numericdisplays, certain of which may not be applicable during all ventilationtherapies. Even when more than one display has been provided, userstypically received limited feedback, if any, from the control systemindicating the effect that changing one particular setting had on theoverall respiratory strategy. If a parameter was to be adjusted, thedisplay would change to display that particular parameter upon actuationof the appropriate controls, and allow entry of a value for thatparameter. However, the user was provided with no visual cue as to howthe change in the parameter value would effect the overall ventilationstrategy, and thus had no assistance in determining whether the valueentered for the parameter was appropriate for the patient.

[0009] What has been needed and heretofore unavailable in patientventilators is a user friendly graphic interface that provides forsimultaneous monitoring and adjustment of the various parameterscomprising a respiratory strategy. Such an interface would alsopreferably guide sophisticated users in implementing ventilationtherapies, provide guidance on the relationships between parameters asthey are adjusted, allow rapid return to safe operation in the eventthat an undesirable strategy was inadvertently entered, provide alarmsthat are easily understood and corrected and present all of the relevantinformation in an easily understood and graphic interface. The presentinvention fulfills these and other needs.

SUMMARY OF THE INVENTION

[0010] Briefly, and in general terms, the present invention is directedto a graphic user interface system for controlling a computer controlledventilator to provide respiratory therapy to a patient. In a broadaspect of the invention, the invention includes a digital processor, atouch sensitive display screen and entry means cooperating to provide auser-friendly graphic interface for use in setting up and carrying out awide variety of respiratory therapies. The processor controls thedisplaying of a plurality of screens, including user selectable graphicon-screen buttons for setting the values of various ventilator operatingparameters for controlling the ventilator. Depending on the on-screenbutton touched, the processor causes different graphics to be displayedon the screens, provides graphic representations of the effect on theoverall respiratory strategy caused by changes to the settings, and mayalso provide displays of patient data, alarm conditions, and otherinformation.

[0011] In one preferred embodiment of the invention, the system includesthe use of a digitally encoded knob for altering selected and displayedvalues of ventilation parameters, with the acceptable values indicatedand unacceptable values alarmed and/or limited to prevent harm to thepatient. The digital encoded rotation of the knob may be analyzed by theprocessor and a magnification factor applied to the knob output toincrease the speed with which displayed values are altered. Themagnification factor may also be used in the event of an overshootcondition to assist a user in recovering from the overshoot.

[0012] In another preferred embodiment of the invention, the processormay detect the connection of a patient to the ventilator when theventilator is powered-up. The processor may then, in response to such adetection, start up the ventilator using a predetermined set ofventilator control settings deemed to be safe for the widest possiblevariety of patients.

[0013] In a further preferred embodiment of the invention, the processormay only display ventilator control settings appropriate for a selectedmode of ventilation. The ranges of values of the appropriate settings,or bounds of the ventilation, may be limited by the processor inresponse to the selected mode of ventilation such that only those valuesdetermined to be appropriate are displayed, thus limiting theopportunity to select incorrect settings. Additionally, the processormay be responsive to specific values entered for certain of theventilator settings to adjust the ranges of values allowed forventilator settings dependent on the certain settings. Further, theprocessor may be programmed to require that a so called “ideal bodyweight” be entered before beginning ventilation of a patient, and thenonly ranges of values for settings that would be appropriate forventilation of a patient with that ideal body weight are displayed.

[0014] In another presently preferred embodiment of the invention, thegraphic user interface system includes at least two touch sensitivescreen displays, a plurality of manual parameter controls, including atleast one control knob that is activated upon selection of a parameterto be controlled and displayed on the screen, and a microprocessorcontroller which controls the logic and arrangement of the screendisplays and the interface with the ventilator. The system of theinvention includes protocols programmed into the microprocessor forentry of parameters within ranges predetermined to be appropriate forthe patient parameters entered, alarms and other audible indications ofinvalid entry associated with entries outside of the acceptable rangesof parameters or inappropriate operation such as startup with a patientconnected to the ventilator, and the ability to lock selected parameterswhile allowing for user variation of other parameters.

[0015] In another presently preferred embodiment of the invention, theuser is provided a graphic interface in which the user is allowed toview and adjust a variety of alarm limits and is able to vary the levelsat which the alarms are set off, within limits that are preset by theprogramming of the microprocessor as representative of values that arenot to be exceeded, either as a function of ideal body weight or generalparameters for all patients. The resultant setting of a filtered set ofalarms may then be used by the user to avoid the setting of parametersthat are likely to result in patient distress or other problems with thetherapy, while still allowing the sophisticated user to configure atherapy that is customized for the particular patient.

[0016] In one presently preferred embodiment, the invention also allowsthe user an “undo” option in which a previously successful setting isreestablished after the user realizes that a series of proposed changesare likely to unworkable for the patient.

[0017] In yet another presently preferred embodiment of the invention,the user is provided with alarm indicators indicating the severity of aparticular alarm. Alarm messages are also displayed in a selected screenarea of the graphic user interface to assist the user in alarmrecognition and understanding. Each alarm message may comprise anidentifying message identifying the alarm being indicated, an analysismessage providing information about the condition that caused the alarmto be indicated, and a remedy message suggesting steps that may be takenby the user to correct the alarm condition.

[0018] In a further currently preferred embodiment of the invention, theprocessor allows the user to configure the graphic user interface toprovide a display of the current and/or proposed breath parameters and agraphic representation of the breath timing controlled by thoseparameters. Such a display allows the visualization of relationshipsbetween breath parameters, and, while parameters are being changed,provides the user with a visual representation of the effect of theproposed changes on the ventilation strategy while simultaneouslyallowing the user to view current settings, thus allowing the user tosimultaneously view “where they are now” and “where they are going tobe.”

[0019] From the above, it may be seen that the present inventionrepresents a quantum leap forward in the user interface available forpatient ventilation. While assisting the sophisticated user in bothvisualizing the ventilation strategy and performance of the patient onthe ventilator, it also guides and controls the less sophisticated userin setup and understanding of the relationships between ventilatorsettings. The invention provides these benefits while enforcingfail-safe functioning in the event of a variety of inadvertent orerroneous settings or circumstances.

[0020] These and other features and advantages of the invention willbecome apparent from the following detailed description, taken inconjunction with the accompanying drawings, which illustrate, by way ofexample, the features of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In the drawings, where like reference numerals indicate like orsimilar components, elements and features across the several figures:

[0022]FIG. 1 is a schematic diagram of showing a patient receivingrespiratory therapy from a ventilator system comprising a graphic userinterface and a respirator constituting one embodiment of the presentinvention;

[0023]FIG. 2 is a schematic diagram, primarily in block form, of thevarious subsystems of of the graphic user interface shown in FIG. 1;

[0024]FIG. 3 is frontal plan view showing external details of graphicuser interface of FIG. 1;

[0025]FIG. 4 is a schematic diagram, primarily in block form, of thesequence of display screens typically displayed by the graphic userinterface of FIG. 3;

[0026]FIG. 5 is an illustration of a ventilator startup screen displayedupon startup of the graphic user interface of FIG. 3;

[0027]FIG. 6 is an illustration of a main controls setup screen used toset the main control settings of the ventilator of FIG. 3;

[0028]FIG. 7 is a schematic diagram, primarily in block form,illustrating how the adjustment of certain settings affects theapplicability of other settings used to control the ventilator of FIG.3;

[0029]FIG. 8 is an illustration of a proposed vent settings screenincluding a breath diagram;

[0030]FIGS. 9A, 9B, and 9C are illustrations depicting the display ofthe breath diagram of FIG. 8 dependent upon the values of the parametersrepresented by the breath diagram;

[0031]FIG. 10 is an illustration of an alarm setup screen includinggraphical representations of various alarms settings, acceptable alarmsetting parameter ranges, and current patient data;

[0032]FIG. 11 is an illustration of the upper display screen of FIG. 3;

[0033]FIG. 12 is an illustration of a “More Alarms” display screendisplayed within the information area of the display screen of FIG. 11;

[0034]FIG. 13 is an illustration of a “Waveforms” display screendisplayed within the information area of the display screen of FIG. 11;

[0035]FIG. 14 is an illustration of an “Apnea Ventilation In Progress”display screen displayed within the information area of the displayscreen of FIG. 11; and

[0036]FIG. 15 is an illustration of an “Apnea Settings” display screendisplayed within the information area of the lower display screen ofFIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] The present invention provides a sophisticated graphic userinterface and ventilator breath display capability that allows greatflexibility in the setup of the ventilator and visualization of theeffect that proposed changes to the ventilator setup may have on theventilation strategy. More particularly, the invention provides agraphic representation of a breath cycle that allows the user tovisually evaluate the effect of such changes, and also to select amongappropriate parameters a parameter to “lock” and hold constant whileother parameters are changed.

[0038] The drawings will now be described in more detail, wherein likereferenced numerals refer to like or corresponding elements among theseveral drawings.

[0039]FIG. 1 shows a patient 1 receiving respiratory therapy from aventilator system 10 having a graphic user interface 20 connected to andcontrolling a breath delivery unit, or respirator 22. The patient isconnected to the respirator 22 by a patient circuit comprising aninspiratory line 2, and expiratory line 4, and a patient connection tube6, all connected by a patient connector (not shown) of a type well-knownin the art. The respirator 22 includes a processor or controller 60which controls the real-time operation of the respirator 22.

[0040]FIG. 2 depicts the graphic user interface 20 of FIG. 1 in moredetail. Generally, the graphic user interface 20 comprises user inputs25, a processor 30 and memory 35 comprising read only memory, randomaccess memory or both. The memory 30 may be used to store currentsettings, system status, patient data and ventilatory control softwareto be executed by the computer. The processor 30 may also be connectedto a storage device, such as battery protected memory, a hard drive, afloppy drive, a magnetic tape drive or other storage media for storingpatient data and associated ventilator operating parameters. Theprocessor 30 accepts input received from the user inputs 25 to controlthe respirator 22. The ventilation control system 20 may also includestatus indicators 45, a display for displaying patient data andventilator settings and an audio generator for providing audibleindications of the status of the ventilator system 10.

[0041] The memory 35 and a memory 65 associated with the respiratorprocessor 60 may be non-volatile random access memory (NVRAM) forstoring important, persistent variables and configuration settings, suchas current breath mode setup. Typically, during normal operation of theventilation control system 20, such an NVRAM functions similarly to atypical random access memory. If, however, a low-voltage condition isdetected, such as may occur during a brown-out or at the beginning of apower failure, the NVRAM automatically stores its data into non-volatilestorage.

[0042] The graphic user interface 20 includes an interface 32 forproviding control signals from the processor 30 to the respiratorprocessor 60 of the respirator 22, and also for receiving signals fromsensors 27 associated with the respirator 22 indicative of patientcondition and the status of the respirator 22. The processor 30 of thegraphic user interface 20 may also receive input representative ofvarious clinical parameters indicating clinical condition of the patient1 and the status of the respiratory therapy from the sensors 27 in therespirator 22. The interface may include, for example, an ethernetconnection of a RS-232 serial interface. A cable 34 having anappropriate number of conductors is used to connect the respirator 22 toan appropriate connector (not shown) of the interface 32.

[0043] A preferred embodiment of the display 50 incorporating a userinterface is illustrated in FIG. 3. Generally, the display 50 comprisesan upper display 60 and a lower display 70, dedicated keys 80, 82, 84,86, 88, 90, 92, 94, 96, 98, 100, 102, 104 and knob 106. As will bedescribed in more detail below, additional user inputs are dynamicallyprovided by on-screen buttons that are drawn on the upper and lowerdisplays 60 and 70. Typically, each dedicated key or on-screen buttonincludes, within the outline of the button, either a graphic icon ortext identifying the purpose of the button to the user. These graphicicons or text enhance the ease of use of what would otherwise be aconfusing array of user inputs. Moreover, the use of graphic icons ortext to identify the function of dynamically generated on-screen buttonsprovides for virtually unlimited opportunities to add functions to thegraphic user interface 20 by upgrading the programming of the processor30 as new functions are desired by the users of the system.Additionally, the use of graphic icons overcomes the potential problemof identifying the functions of a button where language comprehensionmay be a problem, such as the use of the ventilator in a country whereEnglish is not readily understood.

[0044] Referring again to FIG. 3, key 80 is identified with a graphicdesign in the form of a stylized padlock. Actuation of key 80 by anoperator locks the keys and buttons of the graphic user interface 20 toprevent inadvertent altering of the settings of the system. Keys 82 and84 control the contrast and brightness of the displays 60, 70. Key 86bears a stylized graphic design representative of a speaker emittingsound, and a graphic indicative of a volume control. Thus, key 86 iseasily identifiable as a control for altering the loudness of audiblealarm signals provided by the graphic user interface 20. Key 92 bears a“?” and actuation of key 92 activates a help system to assist a user inoperating the graphic user interface 20.

[0045] Keys 94, 96, 98 and 100 control various aspects of theventilator, and are used by an operator to override the automaticsettings of the graphic user interface 20. When key 94 is pressed, theprocessor 30 of the graphic user interface 20 provides a signal over the32 to the processor in the respirator 22 instructing the respiratorprocessor to ventilate the patient with 100% oxygen for two minutes. Theprocessor in the respirator 22 also starts a timer and causes the valueof the time at any given instant to be written to a memory associatedwith the respirator processor. When the value in the respirator memoryis equal to two (2) minutes, indicating that the 100% oxygen gas mixturehas been provided to the patient for two (2) minutes, the respiratorprocessor controls the respirator 22 to stop the flow of the 100% oxygento the patient. If the user presses key 94 during the two (2) minuteduration of the 100% oxygen ventilation, the value of the time stored inthe memory is reset to “0” and timing continues for an additional twominutes. Typically, the respirator processor may be programmed torespond to any number of actuations of key 94 without prompting the userfor validation or before sounding and displaying an alarm.Alternatively, the respirator processor may be programmed to respond toonly a limited number of actuation of key 94 before sending a signalthrough the interface 32 to the processor 30 of the graphic userinterface 20 requesting the processor 30 to provide a visual prompt onthe display 50 and/or to control the audio generator 55 to sound anaudible alarm indicating that an allowed number of actuations of key 94has been exceeded.

[0046] When key 96 is pressed during an exhalation, the processor 30controls the ventilator to immediately provide an inspiration. Actuationof key 98 results in an extension of the expiration phase. Similarly,actuation of key 100 results in a lengthening of the inspiration phase.

[0047] Key 102 is labeled with the text “Clear” and actuation of key 102causes proposed changes to the value of a currently selected setting, tobe discussed in more detail below, to be cleared. Key 104 is labeledwith the text “Accept.” When key 104 is touched, any proposed changes tothe ventilator settings are confirmed, and become the current ventilatorsettings.

[0048] Knob 106 is used to adjust the value of an individual settingselected by pressing either keys 82, 84 and 86 or certain on-screenbuttons. Knob 106 is mounted on a shaft whose rotation is digitallydetected by a rotary encoder/decoder, such that the processor 30receives signals indicating not only the magnitude of the rotation ofknob 106, but also the speed and rate of acceleration and decelerationof the rotation of knob 106. These signals are interpreted by theprocessor 30 to display allowable values for the selected setting. Inone embodiment of the present invention, the processor 30 is responsiveto the signals indicative of the speed of rotation of knob 106 tocalculate a velocity based magnification factor dependent on how fastand how long the user turned the knob that is applied by the processor30 to adjust the increment of the values displayed. The processor 30uses this magnifying factor to increment the displayed values in largerincrements when knob 106 is rotated rapidly, and incrementing thedisplayed values in smaller increments when knob 106 is rotated slowly.

[0049] A common problem using rotating knobs where a magnificationfactor is applied in this manner is that there is inevitable “overshoot”of the desired value. Following an overshoot, the user must reverse thedirection of rotation of the knob. This reduces the speed of rotation ofthe knob to zero, and eliminates the magnification. Elimination of themagnification, however, results in more rotation and time to recoverfrom the overshoot. One novel aspect of the present invention is thatthe processor 30 does not reduce the magnification factor to zero whenthe knob is counter rotated, as described above. Rather, the processor30 applies a magnification factor to the counter rotation to reduce theamount of rotation of the knob 106 necessary to recover from theovershoot. The processor sets a time-based limit on how quickly themagnification factor is allowed to decrease, thus ensuring that somemagnification remains during overshoot recovery.

[0050] Additionally, the processor 30 may provide signals to the audiogenerator 55 to cause the audio generator 55 to provide an audibleindication of the rotation of knob 106. For example, the audio generator55 may generate a “click” for a predetermined amount of rotation of theknob 106 or to signify that an on-screen button or dedicated key hasbeen actuated. The audio generator 0.55 may also provide an audio signalto the user if the maximum or minimum value of the range of values forthe selected setting has been reached, indicating that further rotationof the knob 106 will not cause any larger or smaller values to bedisplayed.

[0051] Referring again to FIG. 3, the display area of the ventilationcontrol system 20 comprises an upper display 60 and a lower display 70.The upper display 60 is divided into four non-overlapping areas. Theseareas are “vital patient data” area 110, an “alarm message” area 120, an“information area” 130 and a “controls”area 140. Area 130 is amultipurpose area that may be used to display, for example only, screensdepicting current alarms, an alarm history log, real-time waveforms,measured patient data that is not otherwise displayed in the vitalpatient data area 110, quick reference information, a log of diagnosticcodes, operational time for system components, a ventilator testsummary, the current ventilator software/hardware configuration, a logof the results from running a short self test, apnea ventilationsettings and safety ventilation settings.

[0052] Similarly, the lower display 70 is divided into fivenon-overlapping areas. These areas are a “main settings” area 150, an“information area” 160, a “controls” area 170, a “symbol definition”area 180 and a “prompt” area 190. Examples of information displayed inarea 160 include, but are not limited to screens displayed duringventilator startup and ventilator setup, apnea setup, alarm setup, newpatient setup, communications setup, date/time setup, miscellaneoussetting not otherwise shown in the main settings area 150 and breathtiming graphs.

[0053] It will be understood that the labeling of the fournon-overlapping areas of the upper display 60 and the labeling of thefive non-overlapping areas of the lower display 70 are not critical tothe present invention, but are for convenience only. Thus, the areascould have other labels, depending on the information desired to beconveyed.

[0054] The display area also includes an alarm display area generallyindicated by reference numeral 108. The alarm display area 108 includesa high urgency alarm indicator 110, a medium alarm urgency indicator 112and a low urgency alarm indicator 114. The alarm urgency indicators 110,112 and 114 may be light emitting diodes or any other means of providinga visual indication of an alarm. Additional indicators (not shown) mayalso be included below the alarm indicators.

[0055] Low urgency alarms are used to inform the user that there hasbeen some change in the status of the patient-ventilator system. Duringa low urgency alarm, the low urgency alarm indicator 114 lights, anaudible alarm having a tone indicating that a low urgency alarm eventhas occurred, and an alarm message is displayed in the alarm messagearea 120 of the upper screen 60. During a medium urgency alarm, themedium urgency alarm indicator lights, a medium urgency audible alarm issounded, and an alarm message is displayed in the alarm message area 120of the upper screen 60. Because medium urgency alarms typically requireprompt attention to correct the cause of the alarm, the medium urgencyindicator may flash, and the audible alarm may sound repeatedly with adistinctive tone.

[0056] High urgency alarms require immediate attention to ensure patientsafety. During a high urgency alarm, the high urgency indicator 110,which may be colored red, flashes, a distinctive audible alarm issounded and an alarm message is displayed in the alarm message area 120of the upper screen 60.

[0057] Referring now to FIG. 4, the overall hierarchical structure ofthe user interface comprising the keys, on-screen buttons and upper andlower display screens will be described. When the user of the ventilatorturns on the power to the graphic user interface 20 and respirator 22 byactuating a power switch typically located on the respirator 22 (notshown), the processor 30 begins to power itself up by initiating a poweron self test (POST). If the user actuates a test button, also typicallymounted on the respirator 22 (not shown) during the time when the POSTis running, the ventilator will start up in a SERVICE mode. If the testbutton is not actuated, the ventilator will start up in a VENTILATORmode.

[0058] When the graphic user interface starts up in the VENTILATOR mode,the lower display 70 of the graphic user interface 20 displays theventilator startup screen 200 depicted in FIG. 5. When the ventilatorstartup screen 200 is displayed, the main settings area 150 of the lowerdisplay has two subareas; the upper subarea 152 displays the mainventilator mode settings, while the lower subarea 154 displays thevalues of the ventilator settings appropriate to the main ventilatormode settings that were in use prior to powering down the graphic userinterface 20 and respirator 22.

[0059] The control area 170 on the lower screen 70 typically containsone or more on-screen buttons (see FIG. 8), but is blank on theventilator startup screen 200, as illustrated in FIG. 5. Thisillustrates the dynamic nature of the various screens that are presentedto the user to assist the user in selecting ventilator settingsappropriate to a given respiratory strategy. At this stage of thestartup process, no settings other than those illustrated are presentedto the user so that the user may not inadvertently enter aninappropriate ventilator setting. Other novel features of the display ofthe present invention further assisting the user will be describedbelow.

[0060] A message instructing the user as to what action to take next isdisplayed in the prompt area 190. As indicated by the message displayedin the prompt area, it is important that the ventilator be setup beforeattaching the ventilator to a patient.

[0061] As is illustrated by display depicted in FIG. 5, on-screenbuttons such as buttons 225, 230 and 240 that are active and may betouched by the user to initiate activity are displayed so that theon-screen buttons appear to have a raised, three dimensional appearance.In contrast, on-screen buttons whose actuation is not appropriate on aparticular screen are displayed having a flat, non-three dimensionalappearance, as, for example, the on-screen buttons displayed in subarea154 of the main settings area 150.

[0062] The information area 160 of the ventilator startup screen 200provides the user with three on-screen buttons to choose from toinitiate the next step in completing the setup of the graphic userinterface 20. The user may touch the SAME PATIENT on-screen button 225followed by the off-screen ACCEPT key 104 to set up the ventilator withthe settings displayed in the main settings area 150. If no previouspatient settings are stored in the memory 35, the SAME PATIENT on-screenbutton will not be displayed. Alternatively, if the ventilator is beingused to provide respiratory therapy to a patient different from thepreviously treated patient, the user may actuate the NEW PATIENTon-screen button 230. Actuation of the NEW PATIENT on-screen button 230will result in the display of a new patient setup screen. The user mayalso choose to perform a short self test (SST) of the ventilator and thegraphic user interface 20 by touching the SST on-screen button 240. TheSST on-screen button 240 will not be displayed if the ventilator isalready connected to a patient.

[0063] The upper display 60 and the lower display 70 incorporate touchsensitive screen elements, such as, for example only and not by way oflimitation, infrared touch screen elements, to allow for actuation ofon-screen buttons, such as on-screen buttons 205, 210, 215, 220, 225,230 and 240. The touch screen elements and the processor 30 operate incoordination to provide visual cues to the user as to the status of theon-screen buttons. For example, as described previously, the on-screenbuttons are displayed in such a manner as to appear to bethree-dimensional. When one of the on-screen buttons is actuated by theuser touching the display screen with a finger, a pencil or otherinstrument, the touch screen elements detect the application of thefinger, pencil or other instrument and provide the processor 30 withsignals from which the screen location where the touch occurred may bedetermined. The processor 30 compares the determined location of thetouch with the locations of the various buttons displayed on the currentscreen stored in the memory 35 to determine the button, and thus theaction to be taken, associated with the location of the touch. Theprocessor then changes the display of the touched on-screen button tomake the button appear to be depressed. The processor may also alter thedisplay of the text incorporated into the three-dimensional on-screenbutton. For example, the SAME PATIENT text displayed on the on-screenbutton 225 normally appears as white letters on a dark or gray buttonwhen the button is in an untouched stated. When the button 225 istouched, the processor 30 may cause SAME PATIENT to be displayed asblack letters on a white button. Additionally, the prompt area 190 maychange to a white background with black letters to draw the user'sattention to the prompt area 190 when a message is displayed in theprompt area 190.

[0064] Typically, the action initiated by touching an on-screen buttonis obtained when the user lifts the finger, pencil or other instrumentfrom the surface of the display screen. However, the processor may alsobe responsive to a user sliding the finger, pencil or other instrumentoff the on-screen button and onto the remaining surface of the displayscreen to reset the on-screen button in its un-actuated state and totake no further action. Thus, the action initiated by the touching ofthe on-screen button may only be obtained when the finger, pencil orother instrument is lifted from the portion of the display screen thatis displaying the on-screen button. This feature allows the user toabandon a button touch without activating the function associated withthe button in the case where the button was touched inadvertently or inerror.

[0065] When the NEW PATIENT on-screen button 230 is touched, theprocessor 30 responds by displaying a new patient setup screen (notshown) and purges any previously entered settings from the memory 35.The new patient setup screen includes an IBW on-screen button fordisplaying and altering the value for the ideal body weight (IBW) of thepatient. The new patient setup screen also includes a CONTINUE on-screenbutton; however, the CONTINUE button is not displayed until the IBWbutton is touched to ensure that the user adjusts the IBW to a suitablevalue. The CONTINUE button is displayed immediately after the IBW buttonis touched. Thus, if the value for IBW currently stored in the memory 35is acceptable, the IBW does not need to be adjusted, and the CONTINUEbutton may be touched to accept the current value of the IBW.

[0066] When the IBW on-screen button is touched, the value for IBWcurrently stored in the memory 35 of the graphic user interface 20 maybe adjusted by the user by rotating the knob 106 to either increase ordecrease the displayed value until the value for the IBW desired by theuser is displayed. The user may then touch the CONTINUE button to storethe new value for IBW in the memory 35. When the CONTINUE button istouched, the processor 30 responds by causing a vent setup screen to bedisplayed. Because the vent setup screen is being displayed in responseto the completion of the new patient setup screen, the vent setup screenis displayed in a new patient mode, and is labeled accordingly.

[0067] The processor 30 is responsive to the entered value for thepatients' IBW to determine the initial values and ranges, or bounds, ofthe values of the various ventilator settings that are appropriate foruse with a patient having that IBW. For example, the range ofappropriate values for the various ventilator settings differ betweenadults and children. The processor will display only values that fallwithin the appropriate range of values for selection by the user duringsetup dependent upon the IBW, and will not accept values for settingsthat fall outside of the determined range. If the user attempts to entera value outside of the appropriate range for that patient's IBW, theprocessor 30 may provide an audible indication of an attempt to enter anout of range value and/or a prompt to the user that the value isinappropriate.

[0068] Referring now to FIGS. 6-8, the layout and functions of the ventsetup screen will now be described. Traditionally, setting up aventilator required a user to navigate through a number of confusing andcomplicated displays. A novel aspect of the present invention is thesimplification of ventilator setup by hierarchically categorizing theventilator controls and settings to minimize the number of choicesavailable to a user on any one screen. The vent setup sequence used toconfigure the ventilator comprises two display phases. These two phaseshave been designed to simplify setup of the ventilator by groupingventilator settings in logically arranged groups. Further, the settingsentered during the first phase determine the settings presented to theuser during the second phase. In this manner, only those ventilatorparameters that are appropriate for the mode settings entered during thefirst phase are displayed. Additionally, the ranges of values, orbounds, of the displayed settings may be further limited as appropriatedepending on the proposed ventilator mode and settings. Moreover, sincesome ventilator parameters may be dependent on the values selected forcertain other ventilator parameters, the ranges of values for thedependent ventilator parameters may be limited in accordance with thesettings of those independent ventilator parameters. In this manner, theuser is presented only with those settings that are appropriatedepending on settings already entered by the user. Such a hierarchicalsequencing and presentation are useful in preventing the inadvertententry of inappropriate ventilator settings.

[0069] Once a value for IBW has been entered, the subsequent phases ofthe New Patient Setup process are similar to the “Vent Setup” sequenceof screens which may be accessed at any time during normal ventilationby touching button 321 (FIG. 8). For example, in the first phase of NewPatient Setup, a screen is displayed entitled “New Patient Setup”instead of “Current Vent Setup” and is preceded by a screen presentingthe proposed setting for IBW. Similarly, in the second phase, the titleof the screen is “New Patient Settings” instead of “Current VentSettings.” Accordingly, the following discussion address the “VentSetup” sequence.

[0070] When the vent setup screen is first activated, or following theIBW screen utilized during the new patient setup procedure describedabove, the Main Controls phase depicted in FIG. 6 is displayed. In theMain Controls phase, only buttons 302, 304 and 306, representing themain control settings, are visible in the information area 160 of thelower display screen 70. As shown in FIG. 8, however, the values for thecurrently selected main controls continue to be displayed in area 152,and the currently selected settings are displayed in area 154 of themain settings area 150 of the lower screen 70. The values displayed inareas 152 and 154 remain visible at all times during ventilation setup;thus it may be assumed that they are displayed unless specific referenceis made to the display of different information in areas 152 and 154.When the main controls screen is being displayed during the “New PatientSetup” sequence, the on-screen buttons in area 154 of the main settingsarea 150 are displayed with a flat, non-three dimensional appearance,indicating that they cannot be actuated. During normal ventilationhowever, the on-screen buttons in area 154 may always be actuated by theuser; thus they are displayed with a raised, three-dimensionalappearance during normal ventilation.

[0071] As depicted in FIG. 7, the present invention decomposes thetraditional mode setting into a simple mode plus separate “mandatorytype” and “spontaneous type” settings. There are three modes: “A/C”, orassist/control mode; “SIMV” or synchronous intermittent mandatoryventilation; and “SPONT”, for spontaneous respiration. Dependent on themode and type selected, the processor 30 will display only thosesettings appropriate to that mode and mandatory type. For example, ifthe user selects “A/C” mode and “PC” mandatory type, the processor 30will display on-screen buttons for changing ventilator settings relatedto pressure control of the ventilation. Similarly, selecting “SPONT”mode and “PS” spontaneous type results in the display of on-screenbuttons for changing ventilator settings related to pressure support.

[0072] Referring again to FIG. 6, Button 302 is labeled with “Mode”;Button 306 is labeled with “Mandatory Type”; and Button 306 is labeledwith “Trigger Type.” Each of the buttons 302, 304 and 306 also displaythe setting currently selected for each of the main control settings.For example, button 302 displays “A/C” indicating that assist/controlmode is selected. Alternatively, where SIMV or SPONT modes are currentlyselected, button 302 will display either SIMV or SPONT as appropriate.When either SIMV or SPONT modes are currently selected, a fourth button,button 308 (not shown) labeled with “Spontaneous Type” may also bedisplayed. Further, when the mode is set to SPONT, a message may bedisplayed below button 304 indicating that the value displayed on button304, “Mandatory Type,” applies to manual inspiration only.

[0073] As with others of the buttons used to make changes to the valuesof various operational parameters used by the processor 30 to controlthe respiratory therapy of a patient, the main control settings on thecurrent vent setup screen are set by touching the desired one of thedisplayed buttons 302, 304, 306 or 308 (not shown), and then rotatingknob 106 until the desired value is displayed. When the desired valuefor the setting is displayed, the user may provisionally accept andstore that value in the memory 35 by touching the continue button 310.Alternatively, if more than one main control setting needs to be changedby the user, the user may defer touching the continue button 310, andmay instead select among the other buttons to change the values of adifferent main control settings. The user may, if so desired, change thevalues of each of the main control settings. When the user has changedall of the desired main control settings, the changed values for each ofthe main control settings may be provisionally accepted, pendingcompletion of the second phase of the ventilator setup procedure, andstored in the memory 35 simultaneously by touching the continue button310. Thus, the values for the main control settings may be accepted andstored in a batch, rather than one setting at a time. This isadvantageous in that entry of multiple settings is easier and less timeconsuming. Batch entry is also useful in that all of the proposed valuesfor the main control settings are displayed, and may be checked forentry errors by the user before being committed storage in the memory35.

[0074] When the continue button 310 is touched, the first phase ofventilator setup is complete and the second phase begins. In the secondphase of ventilator setup, the processor 30 displays a proposed ventsettings screen 320 to prompt the user to complete the vent settingsphase of the setup procedure, as depicted in FIG. 8. The proposed ventsettings screen is displayed in the information area 160 of the lowerdisplay 70 (FIG. 3). This screen includes a display 326 of the maincontrol settings set in the first phase described above, and an area 328where a plurality of buttons are displayed. The buttons displayed in thearea 328 are for setting the values for particular ventilationparameters that are appropriate to the main control setting. Thus, thebuttons displayed in area 328 are dependent upon the values selected forthe main control settings in the first phase of the ventilator setup.This display of only those buttons whose settings are appropriate totheir associated main control settings simplifies the display, thusaiding the user in setting up the ventilator and preventing inadvertenterrors due to user confusion.

[0075] As with the main settings screen displayed during the first phaseof the vent setup procedure, the user may select a parameter to changeby touching one of the on-screen buttons, such as the “P_(I)” on-screenbutton 352. When the user touches button 352, the button appears to bedepressed, and may change color and text contrast as described above.The user then adjusts the value of the setting by turning knob 106 (FIG.3) until the desired value is displayed on the button 352. If the useris satisfied with the value entered for button 352, and the otherdisplayed values, the user may touch the PROCEED button 356, followed bythe ACCEPT key 104 (FIG. 3) to complete the vent setup procedure.Alternatively, the user may touch another one of the on-screen buttons,such as the “f” on-screen button 350. When button 350 is touched, button352 “pops” up, indicating that button 352 is no longer selected, andbutton 350 appears to become depressed. An audible indication that thebutton is touched, such as a “click” may also be provided. In thismanner, the values for all of the settings displayed may be changed oneafter another if desired, or only certain of the settings may bechanged, as desired by the user. The user then may configure theventilator to operate in accordance with all of the changed settings atonce in a batch fashion by touching the PROCEED on-screen button 356,followed by pressing the off-screen ACCEPT key 104.

[0076]FIG. 8 further illustrates additional aspects of the graphicalfeatures provided by the user interface 20 that assist the user insetting up and operating the ventilator. As depicted in FIG. 8, the mainsettings area 152 displays the currently active main settings. Thesesettings are easily compared with the main settings entered during thefirst phase of setup that are now displayed on the proposed ventsettings screen in area 160. For example, as illustrated in FIG. 8, theventilator is currently setup to ventilate in the SIMV mode, and theuser has provisionally changed the mode to A/C, as indicated in thedisplay 326. Another aspect of the invention is the visual promptprovided to a user that a particular setting has been changed. Thisaspect is illustrated by the change in the font used to display thevalue of the setting for “P_(I)”, where the value “15.0” is displayed initalics, indicating that this value has been changed, compared to thenormal font used to display the value “16” for “f”, indicating that thisvalue has not been changed.

[0077] If any of the main settings were changed during the first phaseof the vent setup procedure were changed, the PROCEED on-screen button356 is displayed on the proposed vent settings screen 320. Similarly, ifnone of the main settings were changed, the PROCEED on-screen button isnot displayed until one of the settings displayed during the secondphase of the vent setup procedure is changed. If the user is satisfiedwith the values for the settings that have been entered, the user maytouch the PROCEED on-screen button 356. The user may then completeconfiguration of the ventilator settings, replacing the current ventsettings with the proposed settings, by pressing the off-screen ACCEPTkey 104. The off-screen placement of the ACCEPT key 104 ensures that noinadvertent changes are made to the ventilator settings.

[0078] If the processor 30 determines that the vent setup screen hasbeen activated within a predetermined short period of time, for example,within 45 minutes of the most recent time the vent setup screen was usedto change values of the ventilator settings, the processor 30 maydisplay a PREVIOUS SETUP button on the main settings screen 300 (FIG.6). The processor 30 removes this button from the screen if any changesare made using the screen. If the user touches the PREVIOUS SETUP button(not shown) on the main settings screen, a screen similar to the secondphase display depicted in area 160 (FIG. 8) is displayed, showing valuesfor the settings as they were immediately prior to the last settingchange made using the vent setup screen. The on-screen settings buttonsare all displayed in the flat, non-three dimensional state, indicatingthat they cannot be adjusted. A prompt message is displayed in area 190explaining that accepting the displayed values will result in the entireprevious setup being restored, including old alarm and apnea settings.The previous setup may be re-instated by the user by touching thePROCEED button 356, followed by pressing the ACCEPT key 104. Thisfeature of the present invention allows a user to quickly restore theventilator to the settings state it was in prior to a major setup changein the event that the altered ventilation strategy is not successful. Atime lime is placed on the availability of the previous settings toavoid the possibility of re-imposing the settings when the patient'scondition may have changed substantially. Individual changes to settingsmay be made to settings in the period following a major settings changewithout invalidating the settings stored for the previous setup.However, batch changes, that is, the changing of more than a singlesetting at a time, results in the stored previous settings beingreplaced with the most recent set of settings. This provides the userwith the ability to fine tune the settings made during the major changewithout losing the ability to “UNDO” all of the major changes and returnto the previous settings.

[0079] Referring again to FIG. 8, the proposed vent settings screen 320also includes a graphical representation, or breath diagram 330, of thebreath cycle that will be provided to the patient based on the settingsentered by touching the buttons displayed in area 328 and adjusting theresulting displayed values using the knob 106, as described above. Thebreath diagram 330 includes a time line 332 that is displayed for scalepurposes only, an inspiration bar 334 indicating the portion of thetotal breath duration during which inspiration will take place, anexpiration bar 336 indicating the portion of the total breath durationduring which expiration will take place, an inspiration/expiration ratiodisplay 338 and a total breath time display 346. Besides the graphicalrepresentation of the duration of the inspiration and expirationportions of the total breath cycle, text representing the selected valuefor the durations may be displayed in the respective bars 334 and 336.For example, the inspiration phase of the breath is set to require 1.0seconds and the expiration phase is set to require 2.75 seconds. Thecolors or shading of the inspiration bar 334 and the expiration bar 336are preferably different to facilitate a user distinguishing betweenthem. For example, the inspiration bar 334 may be shaded dark with whitetext, indicating that the breath timing parameter is “locked”, while theexpiration bar 336 may have grey shading and black text. It will beunderstood that this color scheme is only one example of a variety ofcolor schemes that may be used to enhance the graphical representationof the breath cycle to provide a readily comprehensible display ofeither the current status of the ventilation or to assist a user inevaluating the effects of proposed changes to the ventilator settings.

[0080] Lock on-screen buttons 340, 342 and 344 are displayed above thetime line 332 and display the lock status of the settings for theinspiration bar 334, the inspiration/expiration ratio 338 and theexpiration bar 336 respectively. The user may change the lock status ofthe settings by selecting and touching one of the lock icons 340, 342,344. For example, lock button 340 displays a graphical representation ofa closed, or locked, padlock, while lock buttons 342 and 344 displaygraphical representations of open, or unlocked, padlocks. Touching lockbutton 340 will result in the lock button changing to the open, orunlocked state. Similarly, touching lock buttons 342 or 344 will resultin the touched lock button changing to the closed, or locked, state. Theeffect of the “locked” setting is that the setting will not beautomatically changed in accordance with a subsequent change in thebreath rate parameter, while both of the settings for the “unlocked”parameters, here, the expiration time and the ration of inspiration toexpiration, will be changed.

[0081] The display of the lock buttons is dependent upon the selectedmain control settings. For example, in the representative exampledepicted in FIG. 8, main control setting Mandatory Type is set to “PC”,thus causing the lock buttons to appear; if the Mandatory Type is set to“VC”, the lock bottons would not be displayed. When the Mandatory Typeis “PC”, only of the of the three “breath timing” settings, T_(I), T_(E)or I:E is displayed. T_(I) is set by touching the on-screen buttonlabeled T_(I), and adjusting the knob 106 until a desired value isdisplayed. The value will be displayed both on the on-screen buttonT_(I), and in the inspiration bar 334 of the breath diagram 330. Becausethe value for T_(I) is locked, as evidenced by the closed lock button.340, and the dark shading of the inspiration bar 334, changes to thebreath rate do not-result in a change to the inspiration time; only theexpiration time, inspiration/expiration ratio and the total breath timechange. If another time parameter, such as T_(E) was locked, changes tothe rate would not affect T_(E), but T_(I) and theinspiration/expiration time ratio would change.

[0082] The above described relationship is apparent from FIGS. 9A-C. InFIG. 9B, the breath rate has been reduced; thus, the total breath timeis increased, as indicated by the value in total time display 344 b.Since the value for the inspiration time was locked, the relative lengthof the inspiration bar 334 b did not change, while the relative lengthof the expiration bar 336 b increased. A novel aspect of the presentinvention evident from the display depicted in FIG. 9B is the change inthe location of the total breath time display 344 b. In FIG. 9A, thetotal breath time display 344 a is located below the time line 332 a. InFIG. 9B, the expiration bar 336 b has grown larger because of theincreased breath time to the extent that the total breath time display344 b has approached the end of the time line 332 b. The processor 30maintains the location of each of the graphical features of the displaysin the memory 35, and constantly assesses whether the display of agraphical feature, such as the breath diagram 330, on-screen buttons ortext may possibly collide or overlap. In the case depicted in FIG. 9B,the processor 30 determined that the total breath time display 344 bwould be displayed sufficiently close to the end of the time line 332 bthat the total breath time display 344 b would interfere with thedisplay of the numerical scale of the time line 332 b. Accordingly, theprocessor caused the total breath time display 344 b to be displayedabove the time line 332 b to avoid such interference. It will beunderstood that the use of the total breath time display 344 b is forpurposes of example only. Any of the text or numeric values displayed inconjunction with the breath timing diagram 330 may be displayed asnecessary to prevent interference with other graphical elements.

[0083] The processor 30 is also responsive to the values of the settingto change the scale of the time line 332 when appropriate. As depictedin FIG. 9C, the total breath duration 344 c has been increased again,and is now greater than the previous scale of the time line 332 c.Accordingly, the processor 30 has caused the time line 332 c to bedisplayed with a larger scale. As the scale of the time line 332 cenlarges, the relative lengths of the inspiration and expiration bars334, 336 also change. As was described above, if the relative length ofthe inspiration bar 334 c becomes too small to allow the display of thevalue of the inspiration time setting within the bar as depicted, theprocessor may cause the value to be displayed either above, below or tothe left of the time line 332 c in the vicinity of the inspiration bar334 c.

[0084] One advantage of a preferred embodiment of the invention is thatthe main control settings are displayed on both the vent setup screenand in the main setting area of the 152 of the lower display 150. Thus auser may adjust the main settings using either screen. However, it isparticularly advantageous to make adjustments to the main controlsettings using the vent setup screen because only one main setting at atime may be changed in the main settings area 152, while multiplechanges may be made in the vent setup screen and then accepted by theuser and stored in the memory 35 of the graphic user interface 20 by theuser as a batch.

[0085] Referring now to FIG. 10, the alarm setup screen will bedescribed. Touching the “Alarms” button 215 (FIG. 5) on the lower screen70 causes the processor 30 to display the alarm setup screen 400. Thealarm setup screen 400 displays graphical representations for thoseuser-adjustable alarms that are appropriate given the values selectedfor the main control settings. Thus, a user may be presented only withalarm settings required by the ventilation strategy already entered andstored in the memory 35 of the graphic user interface 20. Thisfacilitates setup and prevents errors or omissions due to informationoverload given the relatively small size of the information display area160 on the lower screen 70 of the graphic user interface 20.

[0086] Ease of use is further enhanced in that each graphicalrepresentation 410 a, 410 b, 410 c, 410 d and 410 e of an alarm includesa label 415 identifying the patient data parameter associated with thealarm and a display 420 of its current value. The value for the alarmsetting associated with particular patient data parameter setting isdisplayed on an on-screen button 425. To further enhance the usefulnessand comprehensibility of the graphical representations 410 a, 410 b, 410c, 410 d and 410 e, the processor 30 causes the alarm on-screen button425 to be displayed at a location along the graphical line that isproportional to the value of the setting with respect to total length ofthe graphical line.

[0087] The user may adjust the setting of each of the displayed alarmsettings by touching a selected alarm on-screen button, such as alarmbutton 425, and then rotating the knob 106 (FIG. 3) until the desiredalarm setting is displayed on the alarm button 425. As the value for thealarm setting is changed by rotating the knob 106, the processor changesthe position of the alarm button 425 along the graphical line, providinga visual display of the change to the user. The position of thedisplayed patient data parameter 420 is similarly adjusted.

[0088] Certain alarm settings may also be turned off so that no alarmsounds for selected control settings. One possible display of an alarmin the off state is shown by the location and display of the alarmon-screen button 425 b.

[0089] Some patient data parameters may require the setting of bothupper and lower alarm limit values defining a range of acceptable valuesbeyond which a user desires an alarm to be given, as is depicted by thegraphical representation 410 c. Alternatively, as depicted by thegraphical representation 410 d, a lower limit alarm may be turned off bythe user, while setting an upper limit alarm to a selected value.Similarly, the upper limit alarm may be turned off while a value for alower limit alarm is set. When all of the alarms are set, the user maystore the values for one, or all of the alarm settings in a batch mannerby touching the PROCEED button 430 followed by pressing the off-screenACCEPT key 104.

[0090] Referring now to FIG. 11, one exemplary layout of the upperdisplay screen 60 of the graphic user interface 20 will now bedescribed. As described above, the upper display screen 60 includes fournon-overlapping areas 110, 120, 130 and 140. Generally, the upperdisplay screen 60 provides a user with information regarding the stateof the current ventilation therapy. Vital patient information isdisplayed in the vital patient information area 110. The informationdisplayed in area 110 is always displayed when ventilation is inprogress, even while the lower display screen 70 is being used to modifythe settings controlling the ventilation. One novel aspect of thepresent invention is the display of the current breath type and breathphase in the breath type area 525 shown located in the upper left cornerof the vital patient data area 110. In addition to the “CONTROL” breathtype displayed, the ASSIST OR SPONT breath types may be displayed inaccordance with the values for the main settings set as described above.The breath phase, that is, inspiration or expiration, is indicated byalternately reversing the display of the breath type in the breath typearea 525. For example, the text displayed in the breath type area 525may be displayed as black letters on a white background during theinspiration phase, and as white letters on a black background during theexpiration phase.

[0091] It is not unusual during the course of a ventilation treatmentsession for values of monitored parameters to exceed the limits set forthe various alarms that may be active during the session. The processor30 receives signals from the sensors 27 (FIG. 2) for a variety ofmonitored parameters through the interface 32 and compares the values ofthose inputs to the values associated with the alarm settings stored inthe memory 35. When the processor determines that the value of an inputviolates the value or values for the limit or limits for a particularalarm setting associated with that input stored in the memory 35, theprocessor 30 may cause an audible alarm to be sounded, and displays atext prompt identifying the monitored parameter, the cause of the alarmand a proposed course of action to correct the out of limit condition inthe alarm messages area 120. If an event occurs that is potentiallyharmful to the patient, the processor 30 may also control the ventilatorto abort delivery of the current breath until a user may intervene andcorrect the condition causing the alarm.

[0092] Many alarm conditions, however, may exist that do not requireimmediate correction, but are useful to evaluate the course of therespiratory treatment. Accordingly, all alarms are accumulated in an“Alarm Log” that is a chronological listing of all alarms that haveoccurred and which may be reviewed in area 130 of the upper screen 130(FIG. 3) at any time during or after respiratory treatment. If, for somereason, the alarm log contains records of alarm conditions than may beconveniently stored for latter viewing, the processor 30 may cause theoldest alarm records to be deleted, and thus they will not be availablefor viewing.

[0093] If multiple alarm conditions occur during the course oftreatment, the number of alarm messages may exceed the display areaavailable in the alarm message display area 120. The processor 30 maydisplay those alarms having the highest priority in the display area120, scrolling alarms having a lower priority off the screen. The usermay review alarms having a lower priority by touching the “More Alarms”button 510 displayed in the controls area 140. The scrolled alarmmessages are displayed in the information area 130 of the upper screen60. When the “More Alarms” button 510 is touched, the upper screen 60 istemporarily re-arrange to merge areas 130 and 120 into a combined andlarger active alarms display, as depicted in FIG. 12. Touching the “MoreAlarms” button 510 again causes the processor 30 to redisplay thedefault screen display depicted in the FIG. 11.

[0094] Each alarm message 602 (FIG. 12) includes three messages toassist the user in correcting the cause of the alarm. A base message 604identifies the alarm. As will be described more fully below, the usermay touch the alarm symbol to display a definition of the alarm symbolin the symbol definition area 180 of the lower screen 70 (FIG. 3). Ananalysis message 606 gives the root cause of the alarm, and may alsodescribe dependent alarms that have arisen due to the initial alarm. Aremedy message 608 suggest steps that can be taken by the user tocorrect the alarm condition.

[0095] As illustrated above, the processor 30 may be responsive to usercommands to display various kinds of information in the information area130. For example, FIG. 11 depicts one possible embodiment of the upperscreen 60 having five on-screen buttons for causing various informationand data to be displayed in the information area 130. Touching“Waveform” button 515 causes the processor 30 to display a graphicalplot of the data pertinent to the respiratory therapy being given to thepatient. Similarly, touching the “More Data” button 530 results in theprocessor 30 displaying a screen including a variety of data that may beuseful to the user in assessing the status of the patient and theprogress of the ventilation therapy. It will be understood that thepresent invention is not limited to including only the five on-screenbuttons depicted in FIG. 11. Because the on-screen buttons areimplemented by the processor 30, with suitable programming the processor30 may be enabled to display different or additional on-screen buttonsand perform actions in response to their actuation.

[0096] Touching the “Waveform” button 515 displays a waveform displayscreen 550 as illustrated by FIG. 13. This display allows for real-timeplotting of patient data in the tow plots areas 552 and 554. Differentplots may be displayed in each of the plot areas 552 and 554. A plotsetup screen (not shown) may be accessed by the user by touching the“Plot Setup” button 556. The user may select among plots of pressureversus time, volume versus time, flow versus time and pressure versusvolume.

[0097] The waveform display screen 550 also includes a “Freeze” button558 for freezing any waveform that is currently being plotted in eitherplot area 552 or 554. Touching button 558 causes a flashing “Freezing”message to be displayed until the current plot is completed and preventsany changes being made to the waveform display screen 550 by causing thevarious buttons controlling the scale of the displays, as well asbuttons 556 and 558 to disappear. The only visible button is an“Unfreeze” button (not shown). When the current plot is complete,plotting stops and the on-screen buttons reappear.

[0098] Other displays may also be accessed by touching the on-screenbuttons displayed in the controls area 140 of the upper screen 60. Forexample, touching the “Alarm Log” button 525 causes a screen listing allof the alarm events up to a predetermined maximum number of alarms,including those that have been corrected by the user, that have beensounded during therapy. Touching the “More Screens” button 520 causesthe display of a set of additional on-screen buttons giving access toadditional data not otherwise presented on the main display screens.This feature provides a flexible way to add new features and screenswith minimal impact on the overall design of the graphic user interface.

[0099] In some modes of operation, the respirator processor 60 (FIG. 2)is responsive to signals received from a sensor 27 in the ventilator toprovide inspiration. In this manner, the inspiration may be providedwhen the patient begins to draw a breath in, which is sensed by thesensor and results in the respirator processor 60 causing the ventilatorto provide an inspiration. The respirator processor 60 may be programmedto monitor the rate at which a patient triggers the sensor, and, whenthat rate falls below a predetermined number of breaths per minute, thevalue of which may be stored in the memory 65 (FIG. 2), the respiratorprocessor 60 sends a signal through the interface 32 to the processor 30of the graphic user interface 20. In response to this signal, theprocessor 30 displays an “Apnea Ventilation In Progress” screen 600 inarea 130 of the upper display 60, as depicted in FIG. 14. A variety ofinformation may be displayed on this screen to inform the user of thestatus of the patient and the ventilation. For example, the main controlsettings and the ventilation settings currently active may be displayedalong with a message indicating that apnea ventilation is in progress.Simultaneously, the respirator processor 60 switches to “Apnea” mode andprovides breathing assistance to the patient.

[0100] When the respirator processor 60 automatically institutes “Apnea”mode in response to a lack of inspiration by the patient being treated,the respirator processor 60 controls the apnea ventilation using valuesof various settings entered by the user from an apnea setup screen 650that may be displayed in the information area 160 of the lower screen 70as depicted in FIG. 15 by touching the “Apnea” on-screen button 322 onthe lower screen 70 of the graphic user interface 20. One useful featureof the manner in which the processor controls the displays of thegraphic user interface is illustrated in FIG. 15. As is shown, thevalues for the main control settings and the on-screen buttons forsetting the ventilation settings appropriate for those main controlsettings for the ventilation in process when “Apnea” mode was enteredare displayed in areas 152 and 154 of the lower display screen (FIG. 5).Additionally, the current apnea settings are displayed in theinformation area 160, along with on-screen buttons which can be actuatedin concert with the knob 106 to adjust the apnea settings.

[0101] Referring again to FIG. 5, another novel aspect of the presentinvention will now be described. The lower display screen 70 includes anarea 180 in which the processor 30 may display a variety of messages toassist the user in setting up the graphic user interface. These messagesmay be different from, or in addition to prompts displayed by theprocessor-30 in the prompt area 190 of the lower display screen 70. Onepossible use of the area 180 is to provide a textual definition of agraphic symbol identifying a on-screen button. For example, when a usertouches the “Waveform” on-screen button 515 on the upper display screen60 (FIG. 1), the text “Waveform” may be displayed by the processor 30 inthe display area 180. This feature provides the user with an easilyaccessible means to determine the functionality of any of thegraphically identified on-screen buttons on either the upper or lowerdisplay screens 60, 70 while allowing the elimination of textualinformation from the displayed on-screen button to simplify the display.

[0102] It is generally an unsafe practice to power-up a ventilator witha patient already attached because the ventilator may attempt toventilate the patient in a manner which would be harmful to the patient.The respirator processor 60 is responsive to detection of a such acondition to start an “Safety PCV” ventilation mode and to send a signalto the processor 30 of the graphic user interface 20 to sound an alarm.In this mode, the respirator processor 60 controls the respirator 22using a pre-determined set of ventilator setting in pressure-controlmode. These pre-determined settings are selected to safely ventilate thewidest set of possible patients. Once the new patient, or same patientsetup process is completed as described above, the processor terminatesthe “Safety PCV” mode, and begins ventilating the patient in accordancewith the newly entered settings.

[0103] From the above, it will be appreciated that the present inventionprovides important new capabilities in the display of a graphicrepresentation of a breath cycle for use in evaluating changes toventilation parameters while using a graphic user interface. Whileseveral forms of the invention have been illustrated and described, itwill also be apparent that various modifications can be made withoutdeparting from the spirit and scope of the invention. Accordingly, it isnot intended that the invention be limited, except by the appendedclaims.

We claim:
 1. A ventilator control system, comprising: a ventilatorcontroller, the ventilator controller including means for communicatingwith a user, the controller further comprising: means for enabling theuser to initiate the display of a menu of ventilator related parameters;means for enabling the user to selectively assign values for any of theparameters in the menu; and means for displaying a breath cyclecalculated from the assigned values of the parameters.
 2. The system ofclaim 1, wherein the means for communicating with a user comprises atouch screen.
 3. The system of claim 2, wherein the means for enablingthe user to initiate the display of a menu of ventilator relatedparameters comprises a touch screen display having an image that theuser selects to initiate the display of the menu.
 4. The system of claim1, wherein the means for communicating with the user comprises: meansfor displaying values of the parameters; means for enabling the user toselectively change one of the values so displayed; and means forautomatically updating other ones of the values of the displayedparameters when such a change is made.
 5. The system of claim 1, whereinthe displayed breath cycle comprises: a time scale; an inspiration imagedisposed on the time scale; an expiration image disposed on the timescale, adjacent to, but not overlapping, the inspiration image.
 6. Thesystem of claim 5, wherein the inspiration image comprises a graphicrepresentation of inspiration duration and the expiration imagecomprises a graphic representation of expiration duration, theinspiration and expiration durations being calculated from selectedvalues of the parameters.
 7. The system of claim 5, wherein thedisplayed breath cycle further comprises a displayed value of a totalbreath duration calculated from selected values of the parameters. 8.The system of claim 6, wherein the displayed breath cycle furthercomprises a displayed value of a ratio of the inspiration duration withrespect to the expiration duration.
 9. The system of claim 8, wherein aninspiration time value is displayed in association with the graphicrepresentation of the inspiration duration and an expiration time valueis displayed in association with the graphic representation of theexpiration time.
 10. The system of claim 8, wherein the graphicrepresentation of the inspiration duration is an inspiration bar and thegraphical representation of the expiration duration is an expirationbar, the inspiration and expiration bars having lengths proportional tovalues of the inspiration and expiration time values and the time scale.11. The system of claim 10, wherein the inspiration time value isdisplayed within the inspiration bar if the length of the inspirationbar is sufficient to allow the inspiration time value to be displayedwithin the inspiration bar and the expiration time value is displayedwithin the expiration bar if the length of the expiration bar issufficient to allow the expiration time value to be displayed within theexpiration bar.
 12. The system of claim 11, wherein the inspiration timevalue is displayed adjacent to the inspiration bar if the length of theinspiration bar is not sufficient to allow the inspiration time value tobe displayed within the inspiration bar and the expiration time value isdisplayed adjacent to the expiration bar if the length of the expirationbar is not sufficient to allow the expiration time value to be displayedwithin the expiration bar.
 13. A ventilation system, comprising: a touchscreen for communicating with a user, the touch screen furthercomprising: a ventilator settings screen including a plurality ofventilator related parameters; means for enabling a user to selectivelyassign values for any of the parameters utilizing touch screentechniques; and a breath diagram displayed in association with theventilator settings screen on the touch screen, the breath diagram beinggenerated according to the selected values of the parameters.
 14. Thesystem of claim 13, wherein the breath diagram further comprises aninspiration portion and an expiration portion.
 15. The system of claim14, wherein the breath diagram further comprises a time scale.
 16. Thesystem of claim 14, wherein the breath diagram further comprises adisplayed value for a complete breath cycle, the displayed value beingcalculated from the selected values of the parameters.
 17. The system ofclaim 12, further comprising: a memory for storing programminginstructions, display data and the selected values of the parameters;and a processor connected to the memory and the touch screen, theprocessor being responsive to the means for enabling the user toselectively assign values for any of the parameters displayed on thetouch screen to generate the breath diagram.
 18. The system of claim 17,wherein the breath diagram includes a time scale, an inspiration portionand an expiration portion, the inspiration and expiration portions eachhaving a length calculated by the processor in response to the selectedvalues of the parameters.
 19. The system of claim 18, wherein theinspiration portion length and the expiration portion length aredisplayed in proportion to the time scale.
 20. The system of claim 18,wherein the processor determines a display length for a value of theinspiration time and displays the value for the inspiration time withinthe inspiration portion if the display length for the value of theinspiration time is less than the length of the inspiration portion,other wise the value for the inspiration time is displayed adjacent theinspiration portion.
 21. The system of claim 18, wherein the processordetermines a display length for a value of the expiration time anddisplays the value for the expiration time within the expiration portionif the display length for the value of the expiration time is less thanthe length of the expiration portion, other wise the value for theexpiration time is displayed adjacent the expiration portion.
 22. Thesystem of claim 19, wherein the processor is responsive to changes inthe selected values of the ventilator parameters to adjust the lengthsof the inspiration portion and the expiration portions and to displaythe adjusted inspiration and expiration portions as the changes are madeby the user.
 22. The system of claim 19, wherein one of the inspirationand expiration portions may be locked by the user such that the displayof the locked portion remains changes while the display of the unlockedportion changes in response to changes in the selected values of theventilator parameters.